Aem fail safe o2

[sosick]

So i searched the forums and google, and i cant find anyone using the aem o2. Most ppl if not all are just taping into the factory o2 wires. After install my car wants to die at stops. I only have the two grounds hooked up, red to fuse box, and grey to light switch. Is there something im doing wrong? Is it better to use factory o2?

[Kodename47]

So you've replaced the factory primary or secondary O2 sensor? If its the primary, you can't do that. If it's the secondary then you need to wire it in correctly and then get mapping to suit.

[sosick]

Originally Posted by Kodename47

So you've replaced the factory primary or secondary O2 sensor? If its the primary, you can't do that. If it's the secondary then you need to wire it in correctly and then get mapping to suit.

Its the secondary o2. So if i just put the factory one in and and just tap it i dont need a map?

[steve99]

As @Kodename47 said you need to leave the factory front 02 sensor untouched as its the sensor used for fueling measurements for engine.

If you do wire in the aem to the REAR 02 your going to need tune/map changes as the rear 02 is a narrow band and your going to be feeding ecu with a wideband signal. and its likey going to throw cel codes.

If you dont feed a signal back to ecu probably going to have to "delete" the rear 02 sensor in the tune/map, by zeroing out its compensation tables and disabling associated cel codes.

If you dont need to feed the AEM wideband signal to ECU you would be better getting an extra sensor fitting installed in the exhaust for the AEM and leaving both factory sensors alone.

[sosick]

Originally Posted by steve99

As @Kodename47 said you need to leave the factory front 02 sensor untouched as its the sensor used for fueling measurements for engine.

If you do wire in the aem to the REAR 02 your going to need tune/map changes as the rear 02 is a narrow band and your going to be feeding ecu with a wideband signal. and its likey going to throw cel codes.

If you dont feed a signal back to ecu probably going to have to "delete" the rear 02 sensor in the tune/map, by zeroing out its compensation tables and disabling associated cel codes.

If you dont need to feed the AEM wideband signal to ECU you would be better getting an extra sensor fitting installed in the exhaust for the AEM and leaving both factory sensors alone.

So either way i need a tune for it. I guess ill just leave the aem one on and get a tune from moto east. What would be the best way to do it, if i dont need the fail safe feature?

[steve99]

Originally Posted by sosick

So either way i need a tune for it. I guess ill just leave the aem one on and get a tune from moto east. What would be the best way to do it, if i dont need the fail safe feature?

If you dont want failsafe feature then just get an extra 02 bung welded in for aem.

the failsafe could still be wired to ecu but you would need tune to interpret input.

The ecutek tuners should be able to rescale the stock 02 sensor to read more wideband and they should be able to set up some custom maps in ecutek to monitor afr load and rpm and kill engine power if targets exceeded all on the standard hardware without aem or other external hardware

they can also initiate overboost cut in same manner, that what you pay the money for in ecutek

[sosick]

Originally Posted by steve99

If you dont want failsafe feature then just get an extra 02 bung welded in for aem.

the failsafe could still be wired to ecu but you would need tune to interpret input.

The ecutek tuners should be able to rescale the stock 02 sensor to read more wideband and they should be able to set up some custom maps in ecutek to monitor afr load and rpm and kill engine power if targets exceeded all on the standard hardware without aem or other external hardware

they can also initiate overboost cut in same manner, that what you pay the money for in ecutek

So after work i drove it around for awhile. The issue seemed to have gone away. And im getting about 11.3 at wot. While at idle it jumps from 14.8 to 13.3. Im wondering if the issue had anything to do with me unplugging the battery while i installed the fail safe?

[steve99]

Originally Posted by sosick

So after work i drove it around for awhile. The issue seemed to have gone away. And im getting about 11.3 at wot. While at idle it jumps from 14.8 to 13.3. Im wondering if the issue had anything to do with me unplugging the battery while i installed the fail safe?

unplugging battery just resets ecu learned parameters should cause any big dramas or not starting, might jist feel a little laggy on throttle for a couple of drives, but nothing major should happen if everything is ok

Is you car boosted or na, and what fuel ?

generally idle should be arround 14.7 and steady arroud that bit unusual for it to dip to 13 at idle
light throttle maybe in 13 range

medium throttle maybe mid low 13 to mid 12 maybe a bit richer boosted
wot high 11 or low 12 na and probably roynd mid to low 11 if boosted just very rough estimates

[sosick]

Originally Posted by steve99

unplugging battery just resets ecu learned parameters should cause any big dramas or not starting, might jist feel a little laggy on throttle for a couple of drives, but nothing major should happen if everything is ok

Is you car boosted or na, and what fuel ?

generally idle should be arround 14.7 and steady arroud that bit unusual for it to dip to 13 at idle
light throttle maybe in 13 range

medium throttle maybe mid low 13 to mid 12 maybe a bit richer boosted
wot high 11 or low 12 na and probably roynd mid to low 11 if boosted just very rough estimates

Boosted. Its on moto easts base tune right now, i was breaking in the turbo. And finally got a chance to wot it. Tomorrow i'll log it and send it to moto east and see what they say. And i will check afrs in ecutek to aems. Btw if i took out the rear o2 does that mean i wont see afrs in ecutek? Or does it run off of sensor one? Also i told i read on the forum here that mike from moto east says they disable the rear o2...im gonna go reread.

[steve99]

Originally Posted by sosick

Boosted. Its on moto easts base tune right now, i was breaking in the turbo. And finally got a chance to wot it. Tomorrow i'll log it and send it to moto east and see what they say. And i will check afrs in ecutek to aems. Btw if i took out the rear o2 does that mean i wont see afrs in ecutek? Or does it run off of sensor one? Also i told i read on the forum here that mike from moto east says they disable the rear o2...im gonna go reread.

no the secondary sensor is just used for determining if cat in header is working and some cruise fueling adjustments, you can get away without it if you disable its adjustments in tune.

The front 02 is primary sensor thats used for engine fueling, and ecutek or other systems read this sensor.

Flex kits often hijack the rear 02 sensor input for use as flex sensor input.

[Kodename47]

As per the other thread:

Originally Posted by Kodename47

There are settings that need to be zeroed out if you repurpose the rear sensor input or remove it completely. I would expect that would clear the issue as the secondary sensor does impact fueling.

[Pro60modman]

I know on the old AEM 30-4100 gauges you just ran the blue 0-1v wire to the factory o2 sensor input and coded out the heater control codes. The white wire was the 0-5v wideband output wire. I am actually installing an AEM Boost/Wideband failsafe combination gauge in my Dad's FR-S tmw so if you want to know how to set it up I'll let you know when I'm done.

[sosick]

Originally Posted by Kodename47

As per the other thread:

Yea i read that last night. Ive been searching like crazy on all my options

[Pro60modman]

Here is the failsafe gauge installed on the FR-S

AEM red wire goes to Scion fuse box harness wire Red w/Blue Strip NO SILVER DOTS.

AEM Gray wire goes to purple wire on dimmer switch

AEM Black wire goes to ground on a metal surface

AEM White wire goes to rear o2 sensor input wire

All other wires can be deleted.

I have it set to read boost in the middle and AFR on the outside. When dialing the MAF curve I had it set to read AFR only. The alarm display sets off after a 1/4 second of seeing -11.0 AFR or +12.0 AFR above 4psi. Very user friendly by just hooking up a USB and running the failsafe software. It can be changed on the fly with a laptop while the gauge is on.